The production of needles involves many processing steps and different types of machinery to perform each step. The accuracy and repeatability of the various processes become more critical in the preparation of high quality surgical needles from raw stock. Some of the processes involved in the production of surgical grade needles include straightening spooled wire stock, cutting a length of stock wire to form a needle blank, tapering or grinding points on one end of the blank, providing a bore for receiving suture thread at the other end of the blank, flat pressing a portion of the needle barrel to facilitate easier grasping by surgical instrumentation, and curving the needle where curved needles are desired.
Normally, each processing step is performed by a different piece of machinery. This requires that the needle blanks be manually transferred from one piece of machinery to another as sequential processing steps are carried out. The transfer step increases the time and manpower necessary for needle production.
Generally, there are numerous ways to drill or cut the hole in the end face of a needle blank. For example, the hole may be made by drill machining, electric discharge machining, laser beam machining, electron beam machining and the like. With the advent of microsurgical procedures, surgical sutures have become increasingly smaller in size, thus requiring increased precision in needle production techniques and making it more complex and costly to manufacture the surgical needles. In particular, one aspect of surgical suture manufacturing which has become more difficult and complex for small diameter needles is drilling the hole in the needle blank. The small diameter needle blanks must be presented to the bore-forming device with extreme precision to ensure centrality of the bore formed therein. In addition, as the diameter of the wire decreases, as a general rule so does the length of the needle. Precise handling of short, very fine needle blanks without causing damage to the needle blank is quite difficult to achieve.
A common procedure for making a hole in a surgical needle utilizes laser or electron beam machining. In order to utilize these methods in a production environment, techniques have been developed to sequentially present a series of needle blanks to the beam for cutting. One such technique includes presenting the blank needle from a rotary spool which rotates to sequentially prevent an end face of a needle blank in line with the focal plane of the laser or electron beam. However, one drawback to this technique is that the rotating spool must stop before the beam is impinged on the needle. In order to operate properly the spool must come to a reset at precisely the same portion aligned with the focus point of the beam. If the needle in the rotating spool is not precisely aligned with the focus point of the beam, the hole created in the needle blank would be off center, thereby reducing the accuracy of the production process and ultimately resulting in increased defective quantities of needles. Currently, rotary spool systems are unable to obtain the precise positioning required for laser or electron beam machining. This lack of precision is magnified as the speed in which the blank needle is presented increases. As a result, the reliability and accuracy of rotary spool feeding systems is unacceptable in a high volume production environment.
Another technique utilized has been to bundle needle blanks in a container, digitize an image of the needle blank faces in the bundle and move the laser or electron beam to focus sequentially on each needle blank before firing the beam. These types of beam machining devices also have drawbacks, such as the need to optically determine where each needle blank is and then move the beam to coincide with the longitudinal axis at the center of the needle blank. Such systems are complex and require additional steps in order to determine the precise position of each needle blank. As a result, the speed of producing sufficient quantities to satisfy production needs is decreased.
Therefore, a need exists for an apparatus for producing drilled needle blanks in an accurate and reproducible manner at high speeds. In addition, a need exists for an apparatus for producing drilled needle blanks in a cost effective manner which does not require manual transporting of the needle blanks between different pieces of machinery.